1. Field of the Invention
The invention relates to a biogenic substance detector and biogenic substance detection method for detecting a biogenic substance, such as nucleic acid molecules having a specific base sequence.
2. Description of Related Art
A DNA microarray is one technique of testing whether or not a specific gene from which a certain disease derives exists in specimen material such as blood or tissue cells. The DNA microarray tests whether a target gene exists or not by causing a reaction (hybridization) between a probe gene fixed to a base plate and a gene in a specimen material. Conventionally, means of enhancing reaction efficiency between a specific gene in a specimen material and a probe gene has been devised to improve the accuracy of detecting that specific gene contained in the specimen material.
For example, Japanese Patent No. 3746756 discloses a method for enhancing reaction efficiency by filling a space between a base plate, onto which a probe is fixed, and a plate member and causing a relative motion between the base plate and the plate member, thereby agitating the sample solution. Also, Japanese Patent No. 3557419 discloses a method for enhancing reaction efficiency by distributing fine particles in a sample solution and agitating the sample solution.
In the methods disclosed in Japanese Patents Nos. 3746756 and 3557419, the sample solution is agitated by, for example, rotating a DNA microarray. Meanwhile, as an example of a method for enhancing reaction efficiency without using a mechanism for moving a microarray, Japanese Patent Application Laid-open (Kokai) Publication No. 2007-40969 discloses a biochemical reaction cassette including a fluid resistance unit for reducing the cross-sectional area of a passage in order to control the flow of a fluid in chambers for having a nucleic-acid-detecting probe react with a specimen.
If plural kinds of probes are used for detection with the biochemical reaction cassette disclosed in Japanese Patent Application Laid-open (Kokai) Publication No. 2007-40969, the plural probes are placed in one chamber. As main methods for detecting a substance that has reacted with probes, there are: a method using a fluorescent labeling reagent and a method using a chemiluminescent substance. If the method using the fluorescent labeling reagent is utilized, the fluorescent labeling reagent will be bonded to a substance to be detected. Meanwhile, if the method using the chemiluminescent substance is utilized, an enzyme bonded to a substance to be detected serves as a catalyst to generate a luminescent substance. As a result of using the method using the chemiluminescent substance, the generated luminescent substance will diffuse in one chamber and it is hard to tell which probe from among the plural probes in one chamber has detected the luminescent substance. On the other hand, the method using the fluorescent labeling reagent does not have such a problem of diffusion of the labeling agent. Therefore, the method disclosed in Japanese Patent Application Laid-Open (Kokai) Publication No. 2007-40969 is utilized on the condition that the fluorescent labeling reagent is used for detection after hybridization. However, since the method using the chemiluminescent substance can achieve highly-sensitive detection at a lower cost than the method using the fluorescent labeling reagent, it is preferable to utilize the method using the chemiluminescent substance as a detection method.